This invention relates to the flaring of plastic tubing, and especially polybutylene tubing which has very recently received wide acceptance and approval for installations where copper tubing had previously been the standard material. The invention is concerned with the formation of a flared end on such tubing by which it can be clamped in a suitable two-piece fitting.
The art appears thus far to have had difficulty in conceiving satisfactory apparatus for flaring such plastic tubing. For example, the approach most commonly used requires that a closely fitting threaded mandrel be inserted in the end of the tubing to be flared, and the tube and mandrel are secured in a clamp with the mandrel projecting from the end of the tubing. The flaring member is threaded on the mandrel and includes an annular boss of tapered section which progressively expands the end of the tubing away from the mandrel into a flare. Obvious disadvantages of this approach are that both the clamp and the mandrel must be provided in as many sizes as there are sizes of tubing to be flared, and also that the clamp and flaring unit are separate pieces requiring excessive manual manipulation.